Expressions of neuropeptide Y and Y1 receptor in subcutaneous and visceral fat tissues in normal weight and obese humans and their correlations with clinical parameters and peripheral metabolic factors

The Anti-Obesogenic Effects of Muscadine Grapes through Ciliary Neurotrophic Factor Receptor (Cntfr) and Histamine Receptor H1 (Hrh1) Genes in 3T3-L1 Differentiated Mouse Cells

Obesity and type 2 diabetes are prevalent metabolic diseases that have significant links to several chronic diseases, including cancer, diabetes, hypertension, and cardiovascular disease. Muscadine grape extracts have shown the potential to reduce adiposity and improve insulin sensitivity and glucose control. Thus, this study was designed to determine the potential of muscadine grape berries extract (Pineapple and Southern Home) for its antiobesity properties in 3T3-L1 cells as a model for obesity research. The current study's data indicated the total phenolic content (TPC) and 2,2-diphenyl-1-picrylhydraziyl (DPPH) activity were higher in cultivar (CV) Southern Home, meanwhile, elevated the total flavonoid content (TFC) in Pineapple. Both extracts were safe across the tested range (0-5 mg/mL). A noticeable reduction in lipid accumulation was also found in extract-treated cells. In preadipocytes and adipocytes, the tested extracts showed significant alterations in various genes involved in glucose homeostasis and obesity. The most remarkable findings of the current study are the upregulation of two genes, Cntfr (+712.715-fold) and Hrh1 (+270.11-fold) in CV Pineapple extract-treated adipocytes 3T3-L1 and the high fold increase in Ramp3 induced by both Pineapple and Southern Home in pre-adipose cells. Furthermore, the tested extracts showed a potential to alter the mRNA of various genes, including Zfp91, B2m, Nr3c1, Insr, Atrn, Il6ra, Hsp90ab1, Sort1, and Npy1r. In conclusion, the data generated from the current study suggested that the two extracts under investigation are considered potential candidates for controlling insulin levels and managing obesity.

Appetite- and Weight-Regulating Neuroendocrine Circuitry in Hypothalamic Obesity

Since hypothalamic obesity (HyOb) was first described over 120 years ago by Joseph Babinski and Alfred Fröhlich, advances in molecular genetic laboratory techniques have allowed us to elucidate various components of the intricate neurocircuitry governing appetite and weight regulation connecting the hypothalamus, pituitary gland, brainstem, adipose tissue, pancreas, and gastrointestinal tract. On a background of an increasing prevalence of population-level common obesity, the number of survivors of congenital (eg, septo-optic dysplasia, Prader-Willi syndrome) and acquired (eg, central nervous system tumors) hypothalamic disorders is increasing, thanks to earlier diagnosis and management as well as better oncological therapies. Although to date the discovery of several appetite-regulating peptides has led to the development of a range of targeted molecular therapies for monogenic obesity syndromes, outside of these disorders these discoveries have not translated into the development of efficacious treatments for other forms of HyOb. This review aims to summarize our current understanding of the neuroendocrine physiology of appetite and weight regulation, and explore our current understanding of the pathophysiology of HyOb.

Neuroendocrine Effects on the Risk of Metabolic Syndrome in Children

The endocrine and nervous systems reciprocally interact to manage physiological individual functions and homeostasis. The nervous system modulates hormone release through the hypothalamus, the main cerebrally specialized structure of the neuroendocrine system. The hypothalamus is involved in various metabolic processes, administering hormone and neuropeptide release at different levels. This complex activity is affected by the neurons of various cerebral areas, environmental factors, peripheral organs, and mediators through feedback mechanisms. Therefore, neuroendocrine pathways play a key role in metabolic homeostasis control, and their abnormalities are associated with the development of metabolic syndrome (MetS) in children. The impaired functioning of the genes, hormones, and neuropeptides of various neuroendocrine pathways involved in several metabolic processes is related to an increased risk of dyslipidaemia, visceral obesity, insulin resistance, type 2 diabetes mellitus, and hypertension. This review examines the neuroendocrine effects on the risk of MetS in children, identifying and underlying several conditions associated with neuroendocrine pathway disruption. Neuroendocrine systems should be considered in the complex pathophysiology of MetS, and, when genetic or epigenetic mutations in "hot" pathways occur, they could be studied for new potential target therapies in severe and drug-resistant paediatric forms of MetS.

Current Insights Into the Role of Neuropeptide Y in Skin Physiology and Pathology

Neuropeptide Y is widely distributed within the body and has long been implicated as a contributor to skin disease based on the correlative clinical data. However, until recently, there have been few empirical investigations to determine whether NPY has a pathophysiological role in the skin. Due to appearance-altering phenotypes of atopic dermatitis, psoriasis, and vitiligo, those suffering from these diseases often face multiple forms of negative social attention. This often results in psychological stress, which has been shown to exacerbate inflammatory skin diseases - creating a vicious cycle that perpetuates disease. This has been shown to drive severe depression, which has resulted in suicidal ideation being a comorbidity of these diseases. Herein, we review what is currently known about the associations of NPY with skin diseases and stress. We also review and provide educated guessing what the effects NPY can have in the skin. Inflammatory skin diseases can affect physical appearance to have significant, negative impacts on quality of life. No cure exists for these conditions, highlighting the need for identification of novel proteins/neuropetides, like NPY, that can be targeted therapeutically. This review sets the stage for future investigations into the role of NPY in skin biology and pathology to stimulate research on therapeutic targeting NPY signaling in order to combat inflammatory skin diseases.

Sex Differences in Neuropeptide Y Serum, But Not in Fat Intake and Body Mass Index

Background:  One’s appetite has a role in controlling food intake and maintaining energy balance, but its effect on body metabolism related to obesity is still questionable. The purpose of this study was to determine the levels of neuropeptide Y in healthy people and to see differences in gender and anthropometric parameters. The hypothesis of this study was that there would be differences in neuropeptide Y levels in groups with gender and anthropometric parameter differences.      Methods:   This study was a cross-sectional study involving 62 study subjects, male and female, who did not have chronic diseases or metabolic disorders. This research was conducted from April to September 2020. The parameters examined in this study were neuropeptide Y levels and anthropometric parameters. The statistical analysis performed was the Mann–Whitney test to see the differences between groups.  Results:   The mean age of the research subjects was 40.48 ± 10.85 years, with the same ethnic distribution. The distribution of men and women was more women than men. Based on anthropometric examination, it was found that obesity nutritional status was more common in the female group than in the male group; however, serum neuropeptide Y levels were found to be significantly different between male and female groups (male group was higher) which were mean±standard deviation: 348.37±330.09 ng/L, p=0.036.  Conclusions: The study found significant differences in serum neuropeptide Y levels in male and female groups, with neuropeptide Y levels being higher in men than in women. 

Blood Level of 2-arachidonoyl glycerol (2-AG), Neuropeptide Y and Omentin and Their Correlation with Food Habits in Obese Women

Background:

Despite growing concern about the increasing global burden of obesity, there are still many uncertainties in understanding the pathogenesis of this disease. This study aimed to investigate the serum levels of 2-arachidonoylglycerol (2-AG), neuropeptide Y (NPY), and omentin, concerning dietary patterns in obese women.

Materials and Methods:

This case-control study was carried on an equal number of obese (case group) and normal-weight women (n=45 each). Dietary intake was determined based on the food frequency questionnaire. Serum levels of 2-AG, NPY, and omentin were determined using ELISA.

Results:

The obese group showed significantly higher 2-AG and NPY levels than the controls(P<0.001). There were significant positive correlations between the serum level of 2-AG and calorie intake (r=0.219, P=0.038), carbohydrates (r=0.238, P=0.024), fat (r=0.227, P=0.032), saturated fatty acids (r=0.272, P=0.009), and monounsaturated fatty acids (r=0.265, P=0.012).

Conclusion:

Our study revealed that dietary patterns, in particular, the type of fatty acids used may influence levels of 2-AG, NPY, and omentin, which all are involved in pathways resulting in obesity.

Peripheral-specific Y1 receptor antagonism increases thermogenesis and protects against diet-induced obesity

Obesity is caused by an imbalance between food intake and energy expenditure (EE). Here we identify a conserved pathway that links signalling through peripheral Y1 receptors (Y1R) to the control of EE. Selective antagonism of peripheral Y1R, via the non-brain penetrable antagonist BIBO3304, leads to a significant reduction in body weight gain due to enhanced EE thereby reducing fat mass. Specifically thermogenesis in brown adipose tissue (BAT) due to elevated UCP1 is enhanced accompanied by extensive browning of white adipose tissue both in mice and humans. Importantly, selective ablation of Y1R from adipocytes protects against diet-induced obesity. Furthermore, peripheral specific Y1R antagonism also improves glucose homeostasis mainly driven by dynamic changes in Akt activity in BAT. Together, these data suggest that selective peripheral only Y1R antagonism via BIBO3304, or a functional analogue, could be developed as a safer and more effective treatment option to mitigate diet-induced obesity.

Neuropeptide Y gene variants in obesity, dietary intake, blood pressure, lipid and glucose metabolism: A longitudinal birth cohort study

OBJECTIVE

Neuropeptide Y affects several physiological functions, notably appetite regulation. We analysed the association between four single nucleotide polymorphisms (SNP) in the NPY gene (rs5574, rs16147, rs16139, rs17149106) and measures of obesity, dietary intake, physical activity, blood pressure, glucose and lipid metabolism from adolescence to young adulthood.

METHODS

The sample included both birth cohorts of the Estonian Children Personality Behaviour and Health Study at ages 15 (n = 1075 with available complete data), 18 (n = 913) and 25 (n = 926) years. Linear mixed-effects regression models were used for longitudinal association between NPY SNP-s and variables of interest. Associations at ages 15, 18 and 25 were analysed by ANOVA.

RESULTS

Rs5574 CC-homozygotes had a greater increase per year in waist-to-hip ratio (WHR) and a smaller decrease in daily energy intake and carbohydrate intake from age 15-25 years; fasting glucose and cholesterol were higher in rs5574 CC-homozygotes. Rs16147 TT-homozygotes had higher body weight and a greater increase in sum of 5 skinfolds, waist circumference, WHR and waist-to-height ratio; however, they had lower carbohydrate intake throughout the observation period. Rs16147 TT-homozygotes and both rs16139 and rs17149106 heterozygotes had higher triglyceride levels. All NPY SNP-s were associated with blood pressure: rs5574 TT-and rs16147 CC-homozygotes had a smaller increase in diastolic blood pressure, while rs16139 and rs17149106 heterozygous had lower blood pressure throughout the study.

CONCLUSION

Variants of the NPY gene were associated with measures of obesity, dietary intake, glucose and lipid metabolism and blood pressure from adolescence to young adulthood.

[Effect of a Mediterranean-pattern diet on the metabolic response secondary to weight loss; role of the single nucleotide polymorphism (rs16147) of neuropeptide Y]

Introduction

Background and aims: intervention studies that evaluate the effect of rs16147 on metabolic response and weight change after dietary intervention are scarce. We propose to evaluate the role of the rs16147 genetic variant in the metabolic effects produced by a hypocaloric Mediterranean-pattern diet with high content of omega-9. Material and methods: a sample of 363 obese subjects was recruited. At the baseline visit the patients were randomly assigned to one of two hypocaloric diets for 12 weeks (diet M, Mediterranean pattern; diet C, standard hypocaloric). All patients, at baseline and at 12 weeks, had biochemical and anthropometric variables measured, and genotyping performed for the rs16147 variant. Results: in all subjects, and with both diets, the parameters of adiposity, blood pressure, and circulating leptin improved. In obese subjects with allele (A) insulin levels (GG vs. GA + AA) (-0.9 ± 1.1 IU/L vs. -4.4 ± 1.0 IU/L; p = 0.01) and HOMA-IR (-0.3 ± 0.1 units vs. -1.2 ± 0.3 units; p = 0.02) decreased significantly with diet M. Subjects carrying the minor allele showed a significant decrease in basal insulin levels (GG vs. GA + AA) (0.7 ± 0.3 IU/L vs. -2.2 ± 0.9 IU/L: p = 0.02) and HOMA-IR (-0.3 ± 0.2 units vs. -0.7 ± 0.1 units: p = 0.01) after diet C. This decrease in circulating insulin and HOMA-IR levels in patients with allele A was significantly higher with diet M than with diet C. Conclusions: the A allele of the rs16147 variant produces a better metabolic response in terms of insulin resistance and basal insulin secondary to weight loss with two different hypocaloric diets in obese subjects, with improvement being higher with the Mediterranean diet.

Role of hepatic neuropeptide Y-Y1 receptors in a methionine-choline-deficient model of non-alcoholic steatohepatitis

AIMS

NPY-Y1R plays an important role in dietary regulation. Although germline knockdown of NPY-Y1R in mice alleviates high-fat-diet-induced obesity and increases CPT1α levels in the liver, the role of the Y1 receptor in specific tissues has not been studied.

MAIN METHODS

MCD diet is the most widely used method to establish a model of lean NASH in a short time. We therefore evaluated the role of liver NPY-Y1R in NASH progression.

KEY FINDINGS

In mice with liver-specific knockout of NPY-Y1R (LivKO) and wild-type control littermates fed MCD diet for 4 weeks, NPY-Y1R deficiency significantly decreased body and liver weight. Moreover, NPY-Y1R deletion protected mice against hepatic steatosis and injury. LivKO decreased TG, TC, and FFA levels in the liver and alanine aminotransferase activity in plasma. To clarify the mechanism, we evaluated the key enzymes involved in triglyceride hydrolase and fatty-acid oxidase. Expression of ATGL, CPT1α, and ACO was significantly increased in LivKO mice, whereas expression of fatty-acid synthase was significantly decreased. mRNA expression analysis revealed a marked reduction of genes involved in de-novo lipogenesis and monosaturated fatty-acid synthesis, including sterol-regulatory element-binding protein 1c and fatty-acid synthase. Moreover, liver injury-related factors were significantly decreased in LivKO mice, such as TNF-α, inducible nitric oxide synthase, and MCP-1. Thus, NPY-Y1R deficiency in the liver alleviates lipid deposition and injury. However, NPY-Y1R did not affect inflammation and fibrosis.

SIGNIFICANCE

NPY-Y1R deficiency in the liver directly suppresses not only hepatic steatosis, but also liver injury, and thus provides a treatment option for NASH.

NPY1R-targeted peptide-mediated delivery of a dual PPARα/γ agonist to adipocytes enhances adipogenesis and prevents diabetes progression

Objective

PPARα/γ dual agonists have been in clinical development for the treatment of metabolic diseases including type 2 diabetes and dyslipidemia. However, severe adverse side effects led to complications in clinical trials. As most of the beneficial effects rely on the compound activity in adipocytes, the selective targeting of this cell type is a cutting-edge strategy to develop safe anti-diabetic drugs. The goal of this study was to strengthen the adipocyte-specific uptake of the PPARα/γ agonist tesaglitazar via NPY₁R-mediated internalization.

Methods

NPY₁R-preferring peptide tesaglitazar-[F⁷, P³⁴]-NPY (tesa-NPY) was synthesized by a combination of automated SPPS and manual couplings. Following molecular and functional analyses for proof of concept, cell culture experiments were conducted to monitor the effects on adipogenesis. Mice treated with peptide drug conjugates or vehicle either by gavage or intraperitoneal injection were characterized phenotypically and metabolically. Histological analysis and transcriptional profiling of the adipose tissue were performed.

Results

In vitro studies revealed that the tesaglitazar-[F⁷, P³⁴]-NPY conjugate selectively activates PPARγ in NPY₁R-expressing cells and enhances adipocyte differentiation and adiponectin expression in adipocyte precursor cells. In vivo studies using db/db mice demonstrated that the anti-diabetic activity of the peptide conjugate is as efficient as that of systemically administered tesaglitazar. Additionally, tesa-NPY induces adipocyte differentiation in vivo.

Conclusions

The use of the tesaglitazar-[F7, P34]-NPY conjugate is a promising strategy to apply the beneficial PPARα/γ effects in adipocytes while potentially omitting adverse effects in other tissues.

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Tesaglitazar-NPY targets adipocytes via NPY₁R receptor-mediated internalization.

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Peptide-drug conjugate is specifically delivered to NPY₁R-expressing cells.

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Release of tesaglitazar in adipocytes activates PPARγ.

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Drug delivery enhances adipocyte differentiation and adiponectin expression.

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Peptide conjugate exhibits antidiabetic activity in vivo.

Modified Peptide YY Molecule Attenuates the Activity of NPY/AgRP Neurons and Reduces Food Intake in Male Mice

To study the effects of an analog of the gut-produced hormone peptide YY (PYY3-36), which has increased selectivity for the Y2 receptor; specifically, to record its effects on food intake and on hypothalamic neuropeptide Y/agouti-related peptide (NPY/AgRP) neuron activity. NNC0165-1273, a modified form of the peptide hormone PYY3-36 with potent selectivity at Y2 receptor (>5000-fold over Y1, 1250-fold over Y4, and 650-fold over Y5 receptor), was tested in vivo and in vitro in mouse models. NNC0165-1273 has fivefold lower relative affinity for Y2 compared with PYY3-36, but >250-, 192-, and 400-fold higher selectivity, respectively, for the Y1, Y4, and Y5 receptors. NNC0165-1273 produced a reduction in nighttime feeding at a dose at which PYY3-36 loses efficacy. The normal behavioral satiety sequence observed suggests that NNC0165-1273 is not nauseating and, instead, reduces food intake by producing early satiety. Additionally, NNC0165-1273 blocked ghrelin-induced cFos expression in NPY/AgRP neurons. In vitro electrophysiological recordings showed that, opposite to ghrelin, NNC0165-1273 hyperpolarized NPY/AgRP neurons and reduced action potential frequency. Administration of NNC0165-1273 via subcutaneous osmotic minipump caused a dose-dependent decrease in body weight and fat mass in an obese mouse model. Finally, NNC0165-1273 attenuated the feeding response when NPY/AgRP neurons were activated using ghrelin or more selectively with designer receptors. NNC0165-1273 is nonnauseating and stimulates a satiety response through, at least in part, a direct action on hypothalamic NPY/AgRP neurons. Modification of PYY3-36 to produce compounds with increased affinity to Y2 receptors may be useful as antiobesity therapies in humans.

Different effects of high-protein/low-carbohydrate versus standard hypocaloric diet on insulin resistance and lipid profile: Role of rs16147 variant of neuropeptide Y

BACKGROUND AND AIMS

Few studies have assessed the effect of the NPY gene rs16147 variant on metabolic response following a dietary intervention. We evaluated the effect of rs16147 on body weight and biochemical changes after a high-protein/low-carbohydrate hypocaloric diet compared with a standard severe hypocaloric diet over 9 months.

MATERIALS AND METHODS

A population of 270 obese individuals was enrolled. At baseline, participants were randomly allocated to one of two hypocaloric diets, high protein (Diet HP) or standard (Diet S), for a period of 9 months.

RESULTS

After both diets, all genotypes showed decreased body mass index, weight, fat mass, waist circumference, and leptin levels. Participants with the minor allele (A) assigned to the HP diet showed decreases in total cholesterol (-6.5 ± 4.8 vs 10.1 ± 4.1 mg/dL; p < 0.05), LDL cholesterol (-5.9 ± 3.8 vs 9.6 ± 2.4 mg/dL; p < 0.05), triglycerides (-1.0 ± 4.8 vs 16.2 ± 4.1 mg/dL; p < 0.05), insulin (-0.5 ± 2.8 vs 1.7 ± 2.1 UI/L; p < 0.05), HOMA-IR (-0.2 ± 2.1 vs 0.5 ± 2.0 units; p < 0.05), and CRP (-0.3 ± 0.4 vs 1.3 ± 0.2 mg/dL; p < 0.05). Participants with the minor allele assigned to diet S also showed decreases in total cholesterol (-6.1 ± 4.1 vs 14.4 ± 3.1 mg/dL; p < 0.05), LDL-cholesterol (-3.1 ± 2.8 vs 15.0 ± 3.1 mg/dL; p < 0.05), triglycerides (-6.9 ± 4.1 vs 13.2 ± 4.0 mg/dL; p < 0.05), insulin (-0.3 ± 2.1 vs. -1.2 ± 0.2 UI/L: p < 0.05), HOMA-IR (-0.3 ± 2.1 vs. -1.6 ± 1.1 units: p < 0.05), and CRP (-0.4 ± 0.1 vs 1.1 ± 0.2 mg/dL; p < 0.05).

CONCLUSION

In obese Caucasians, the presence of the A allele of the rs16147 genetic variant produces a better metabolic response that is secondary to weight loss with two different hypocaloric diets.

Placental Neuropeptide Y ( NPY) and NPY receptors expressions and serum NPY levels in preeclampsia

IMPACT STATEMENT

Neuropeptide Y (NPY) has been reported as a vasoconstrictive substance which might be associated with preeclampsia. The novel findings of this study were that Y1R, Y2R, and Y5R expressions were significantly lower in the PE than the NP group. Moreover, the NPY receptor expression ratio between the PE/NP groups was lowest for Y2R (0.27) compared to Y1R (0.42) and Y5R (0.40) suggestive of a reduction of this receptor in the preeclampsia group. Our results suggested that decreased Y2R mRNA in the PE group might be associated with abnormalities of placental angiogenesis which probably contributes to the pathophysiology of preeclampsia.

Role of neuropeptide Y gene variant (rs161477) in liver histology in obese patients with non-alcoholic fatty liver disease

BACKGROUND AND RATIONALE

This study was intended to assess the influence of the rs16147 variant of the NPY gene on liver histology in patients with non-alcoholic fatty liver disease (NAFLD).

MATERIAL AND METHODS

Eighty-nine patients with NAFLD were recruited into the study. Serum chemistry tests were done including lipid profile, transaminases, adipokines, and insulin resistance. Genotype of polymorphism (rs161477) of the NPY gene was studied.

RESULTS

Twenty-three patients (25.0%) had the GG genotype (wild type) and sixty-six patients (75%) the GA (n=39) or AA (n=27) (mutant) types. Patients with A allele had a lower percentage of lobular inflammation and steatohepatitis (lobular inflammation plus ballooning) than those with wild genotype. Patients with A allele showed lower SAF (Steatosis, Activity, Fibrosis) scores than non-A allele carriers (5.4±2.7 points vs. 4.1±1.1 points; p=0.01). In the analysis without fibrosis (NAS score), the same differences were detected (4.5±1.8 points vs. 3.4±1.8 points; p=0.01). In the logistic regression analysis A allele carriers showed lower odds for inflammation (OR 0.11, 95% CI 0.02-0.84, p=0.03) and steatohepatitis (OR 0.39, 95% CI 0.14-0.86, p=0.04) after adjusting for age, sex, and body mass index.

CONCLUSIONS

A variant of polymorphism rs16147 of the NPY gene is independently associated to a lower percentage of steatohepatitis and lobular inflammation in obese subjects with biopsy-proven NAFLD.

Adipose Y5R mRNA is higher in obese than non-obese humans and is correlated with obesity parameters

Neuropeptide Y is mainly expressed in the central nervous system to regulate food intake via its receptors, Y receptors, and in various peripheral tissues including adipose tissue. The objectives of this study were to compare Y5R mRNA and adipocyte parameters consisting of area, width, height, and perimeter either between obese and non-obese subjects or between subcutaneous and visceral fat as well as to compare between NPY, Y1R, Y2R, and Y5R mRNA expressions in subcutaneous and visceral adipose tissues. In subcutaneous and visceral adipose tissues, Y5R was greater in obese than in non-obese humans (both P < 0.05). Y1R mRNA expression was highest followed by Y5R, Y2R, and NPY mRNA expressions, respectively, in subcutaneous and visceral adipose tissues. Visceral Y5R mRNA had positive correlations with body weight, body mass index, waist circumference, hip circumference (R ≍ 0.4), and visceral Y1R mRNA (R = 0.773), but had a negative correlation with the quantitative insulin sensitivity check index (R=-0.421) (all P < 0.05). Subcutaneous and visceral adipocyte parameters were positively correlated with body weight, waist circumference, hip circumference, and waist-to-hip ratio, with greater values of correlation coefficient shown in visceral (R ≍ 0.5-0.8) than in subcutaneous adipocytes (R ≍ 0.4-0.6, all P < 0.05). The parameters of visceral adipocytes had positive correlations with serum NPY levels (R ≍ 0.4, all P < 0.05). Y5R mRNA in visceral adipose tissue is related to increased obesity and reduced insulin sensitivity. The dominant Y receptors in subcutaneous and visceral adipose tissue might be the Y1R and Y5R. Visceral adipocytes show higher correlations with obesity parameters than subcutaneous adipocytes, suggestive of an increased risk of metabolic syndrome in visceral obesity. Y1R and Y5R in visceral adipose tissue might be targets of drug development in prevention or treatment of adiposity. Impact statement Obesity, defined as excess fat accumulation, has been increasingly diagnosed worldwide causing adverse health consequences. The novel findings of this study were that Y5R mRNA expression in both subcutaneous and visceral fat was higher in obese than non-obese subjects. Furthermore, Y5R only in visceral fat, not subcutaneous fat, was positively correlated with visceral Y1R and obesity parameters but it was negatively correlated with the QUICKI. Moreover, we found that Y1R expression was highest followed by Y5R and Y2R, respectively, in both subcutaneous and visceral fat. Our results suggested that Y5R in visceral fat was associated with increased obesity and decreased insulin sensitivity. Y1R and Y5R might be the dominant receptors that mediate the effect of NPY-induced fat accumulation in both subcutaneous and visceral adipose tissues. Y1R and Y5R in visceral adipose tissue might be targets of drug development in prevention or treatment of obesity.

Neuropeptide Y promotes adipogenic differentiation in primary cultured human adipose-derived stem cells

Neuropeptide Y (NPY) is an important neurotransmitter in the control of energy metabolism. Several studies have shown that obesity is associated with increased levels of NPY in the hypothalamus. We hypothesized that the release of NPY has coordinated and integrated effects on energy metabolism in different tissues, such as adipocyte tissue, resulting in increased energy storage and decreased energy expenditure. Whether NPY has role in the molecular mechanism of human adipocyte tissue remains unclear. We established the model of human adipose derived stem cells (hADSCs) from human adipose tissue and differentiated it into adipocytes in the presence of NPY at different concentrations (10^-15-10^-6 mmol/L). We then assessed hADSCs proliferation and differentiation by quantifying lipid accumulation and examining the expression levels of related adipocyte markers after differentiation. Furthermore, the specific markers of white adipocyte tissue (WAT) in hADSCs were also analyzed. The results showed that low doses of NPY stimulated hADSCs proliferation (p < 0.05), while high doses of NPY inhibited hADSCs proliferation (p < 0.05). NPY significantly promoted lipid accumulation and increased the size of lipid droplets during human adipogenic differentiation; the levels of adipocyte markers PPAR-γ and C/EBPα were also increased. At the same time, NPY also increased the levels of WAT markers Cidec and RIP140 after adipocyte differentiation. The results suggested high dose NPY inhibits the proliferation of hADSCs while promotes adipocyte differentiation and increases the expression of WAT markers. This may be the reason why increased levels of NPY can lead to a rise in body weight.

Association Study of Arcuate Nucleus Neuropeptide Y Neuron Receptor Gene Variation And Serum Npy Levels in Clozapine Treated Patients With Schizophrenia

Background

Antipsychotic-induced weight gain (AIWG) leads to metabolic consequences and comorbidity, social stigmatization and nonadherence in patients with schizophrenia. Neuropeptide Y (NPY) has an important role in appetite and body weight regulation. Associations between AIWG and serum NPY levels, and genetic polymorphisms (SNPs) associated with its serum levels have been little studied in these patients.

Subjects and methods

Associations between serum NPY concentration and other metabolic and inflammatory markers, and 215 SNPs in 21 genes (NPY gene, NPY receptor genes and genes encoding arcuate nucleus NPY neuron receptors) were studied in 180 patients with schizophrenia on clozapine treatment.

Results

The serum levels of NPY correlated with levels of resistin (r = 0.31, P < 0.001) and age (r = 0.22, P = 0.003). In the general linear univariate model the best-fitting model with explanatory factors age, serum resistin level, serum insulin level, BMI and gender explained 18.0% (P < 0.001) of the variance of serum NPY. Genetic risk score (GRSNPY) analysis found twelve significant (P < 0.05) serum NPY concentration related SNPs among α7 nicotinic acetylcholine receptor gene CHRNA7, insulin receptor gene INSR, leptin receptor gene LEPR, glucocorticoid receptor (GR) gene NR3C1, and NPY gene. However, after permutation test of gene score the predictive value of GRSNPY remained non-significant (P = 0.078).

Conclusions

Serum NPY level does not seem to be a feasible biomarker of AIWG. Serum NPY level alterations are not significantly associated with the candidate gene polymorphisms studied.

Association of Neuropeptide Y Gene rs16147 Polymorphism with Cardiovascular Risk Factors, Adipokines, and Metabolic Syndrome in Patients with Obesity

BACKGROUND AND AIMS

The NPY gene has 4 exons, and it is located at 7p15.1. The main genetic variant described in this gene is rs16147. The aim of this study was to investigate the relationship of NPY rs16147 with body weight, insulin resistance, serum adipokine levels, and risk of metabolic syndrome (MetS).

METHODS

A population of 1,005 obese patients was analyzed in a cross-sectional survey. Weight, fat mass, waist circumference, blood pressure, basal glucose, C-reactive protein, insulin, insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]), lipid profile, and adipocytokine (leptin, adiponectin, and resistin) levels were measured. The genotype of the NPY gene polymorphism (rs16147) was studied.

RESULTS

Body mass index (1.0 ± 0.1; p < 0.05), weight (2.8 ± 0.4 kg; p < 0.05), fat mass (1.8 ± 0.3 kg; p < 0.05), waist circumference (1.9 ± 0.2 cm; p < 0.05), leptin level (15.4 ± 8.2 ng/mL; p < 0.05), insulin level (5.1 ± 1.3 mIU/L; p < 0.05), and HOMA-IR (1.4 ± 0.1 units; p < 0.05) were lower in A allele carriers than in non-A allele carriers in males. Males with an A allele had a lower percentage of MetS (54.8 vs. 69.1%; p < 0.05), central obesity (94.5 vs. 100%; p < 0.05), and hyperglycemia (24.7 vs. 33.8%; p < 0.05) than non-A allele carriers. Logistic regression analysis indicated that male non-A allele carriers had an increased risk of MetS (odds ratio [OR] = 1.26, 95% confidence interval [CI] = 1.17-1.83; p = 0.034), an increased risk of central obesity (OR = 1.08, 95% CI = 1.02-1.11; p = 0.044), and an increased risk of hyperglycemia (OR = 1.20, 95% CI = 1.09-1.79; p = 0.028) after adjusting for age.

CONCLUSIONS

In obese males, the rs164147 polymorphism of the NPY gene is associated with leptin, insulin level, HOMA-IR, and an increased risk of MetS and its related phenotypes, such as central obesity and hyperglycemia.

Neuroendocrinological and Epigenetic Mechanisms Subserving Autonomic Imbalance and HPA Dysfunction in the Metabolic Syndrome

Impact of environmental stress upon pathophysiology of the metabolic syndrome (MetS) has been substantiated by epidemiological, psychophysiological, and endocrinological studies. This review discusses recent advances in the understanding of causative roles of nutritional factors, sympathomedullo-adrenal (SMA) and hypothalamic-pituitary adrenocortical (HPA) axes, and adipose tissue chronic low-grade inflammation processes in MetS. Disturbances in the neuroendocrine systems for leptin, melanocortin, and neuropeptide Y (NPY)/agouti-related protein systems have been found resulting directly in MetS-like conditions. The review identifies candidate risk genes from factors shown critical for the functioning of each of these neuroendocrine signaling cascades. In its meta-analytic part, recent studies in epigenetic modification (histone methylation, acetylation, phosphorylation, ubiquitination) and posttranscriptional gene regulation by microRNAs are evaluated. Several studies suggest modification mechanisms of early life stress (ELS) and diet-induced obesity (DIO) programming in the hypothalamic regions with populations of POMC-expressing neurons. Epigenetic modifications were found in cortisol (here HSD11B1 expression), melanocortin, leptin, NPY, and adiponectin genes. With respect to adiposity genes, epigenetic modifications were documented for fat mass gene cluster APOA1/C3/A4/A5, and the lipolysis gene LIPE. With regard to inflammatory, immune and subcellular metabolism, PPARG, NKBF1, TNFA, TCF7C2, and those genes expressing cytochrome P450 family enzymes involved in steroidogenesis and in hepatic lipoproteins were documented for epigenetic modifications.

Circulating Levels of Orexin-A, Nesfatin-1, Agouti-Related Peptide, and Neuropeptide Y in Patients with Hyperthyroidism

BACKGROUND

There is insufficient information about the appetite-related hormones orexin-A, nesfatin-1, agouti-related peptide (AgRP), and neuropeptide Y (NPY) in hyperthyroidism. The aim of the present study was to investigate the effects of hyperthyroidism on the basal metabolic rate (BMR) and energy intake, orexin-A, nesfatin-1, AgRP, NPY, and leptin levels in the circulation, and their relationship with each other and on appetite.

METHODS

In this prospective study, patients were evaluated in hyperthyroid and euthyroid states in comparison with healthy subjects. Twenty-one patients with overt hyperthyroidism and 33 healthy controls were included in the study.

RESULTS

Daily energy intake in the hyperthyroid state was found to be higher than that in the euthyroid state patient group (p=0.039). BMR was higher in hyperthyroid patients than the control group (p=0.018). Orexin-A was lower and nesfatin-1 was higher in hyperthyroid patients compared to the controls (p<0.001), whereas orexin-A increased and nesfatin-1 decreased after euthyroidism (p=0.003, p<0.001). No differences were found in the AgRP, NPY, and leptin levels between the hyperthyroid and euthyroid states and controls (p>0.05). Orexin-A correlated negatively with nesfatin-1 (p=0.042), BMR (p=0.013), free triiodothyronine (fT3; p<0.001), and free thyroxine (fT4; p<0.001) and positively with thyrotropin (TSH; p<0.001). Nesfatin-1 correlated negatively with orexin-A (p=0.042) and TSH (p<0.001) and positively with fT3 (p=0.005) and fT4 (p=0.001). In the regression analysis, "diagnosis of hyperthyroidism" was the main factor affecting orexin-A (p<0.001).

CONCLUSIONS

Although it seems that no relationship exists among orexin-A, nesfatin-1, and increased appetite in hyperthyroidism, the orexin-A and nesfatin-1 levels are markedly affected by hyperthyroidism.

Regulation of energy homeostasis by the NPY system

Obesity develops when energy intake exceeds energy expenditure over time. Numerous neurotransmitters, hormones, and factors have been implicated to coordinately control energy homeostasis, centrally and peripherally. However, the neuropeptide Y (NPY) system has emerged as the one with the most critical functions in this process. While NPY centrally promotes feeding and reduces energy expenditure, peptide YY (PYY) and pancreatic polypeptide (PP), the other family members, mediate satiety. Importantly, recent research has uncovered additional functions for these peptides that go beyond the simple feeding/satiety circuits and indicate a more extensive function in controlling energy homeostasis. In this review, we will discuss the actions of the NPY system in the regulation of energy balance, with a particular focus on energy expenditure.

The effect of neuropeptide Y on brown-like adipocyte's differentiation and activation

Despite its wide distribution in the central nervous system, the presence of Neuropeptide Y (NPY) in peripheral tissues has been detected. White adipose tissue (WAT) is a new site of NPY synthesis and secretion. The development of brown-like adipocytes in WAT is controlled by hypothalamic NPY neurons through interaction with sympathetic nervous system (SNS). However, whether peripheral NPY has a direct effect on induction of the Uncoupling protein1 (UCP1)-positive adipocytes is unknown. We have used adipocytes derived from C3H10T1/2 stem cells as a model of brown-like adipocyte, and investigated the role of NPY in their differentiation and activation. In general, NPY had no effect on brown adipogenesis of C3H10T1/2 stem cell, but suppressed db-cAMP activation of brown-like adipocytes, which was due to blunting brown fat-relevant gene expression and mitochondrial function. NPY showed suppression in a receptor-dependent manner, inhibition of endogenous cAMP production and cAMP-PKA-dependent pathways p38 MAPK and CREB phosphorylation were involved in the downstream mechanisms. A novel role of NPY in the peripheral is presented, which may help decrease energy expenditure in WAT of obese subjects.

Dose-dependent effects of neuropeptide Y on the regulation of preadipocyte proliferation and adipocyte lipid synthesis via the PPARγ pathways

The objective of this study was to investigate the impact of neuropeptide Y (NPY) on preadipocyte proliferation and differentiation. Preadipocytes were incubated with a range of concentrations of NPY (10(-15)M - 10(-7)M). After NPY-induced differentiation, the extent of preadipocyte adipogenesis was evaluated. The expressions levels of related adipocyte markers such as PPARγ, C/EBPα and DLK-1 were examined by real-time PCR (RT-PCR) or western blot analysis. Furthermore, the mitogen-activated protein kinase (MAPK) signaling pathway proteins were also analyzed by western blot. Our results showed that low doses of NPY stimulated preadipocyte viability and proliferation, while high NPY doses inhibited cell viability. At high concentrations of NPY significantly promoted lipid accumulation and increased the size of lipid droplets. DLK-1 mRNA expression was inhibited, but the expression levels of PPARγ and C/EBPα were increased during differentiation with the presence of high concentration of NPY. High-dose NPY also suppressed the phosphorylation of the extracellular signal-regulated kinase (ERK) 1/2 protein. We conclude that NPY has a biphasic effect on preadipocyte proliferation. A high dose inhibits the proliferation of 3T3-L1 cell while promotes adipocyte differentiation, increasing lipid accumulation especially enlarged lipid droplets' size. NPY may lead to a better understanding for drug development to prevent hyperplastic obesity and hypertrophic obesity.

Hypothalamus-adipose tissue crosstalk: neuropeptide Y and the regulation of energy metabolism

Neuropeptide Y (NPY) is an orexigenic neuropeptide that plays a role in regulating adiposity by promoting energy storage in white adipose tissue and inhibiting brown adipose tissue activation in mammals. This review describes mechanisms underlying NPY's effects on adipose tissue energy metabolism, with an emphasis on cellular proliferation, adipogenesis, lipid deposition, and lipolysis in white adipose tissue, and brown fat activation and thermogenesis. In general, NPY promotes adipocyte differentiation and lipid accumulation, leading to energy storage in adipose tissue, with effects mediated mainly through NPY receptor sub-types 1 and 2. This review highlights hypothalamus-sympathetic nervous system-adipose tissue innervation and adipose tissue-hypothalamus feedback loops as pathways underlying these effects. Potential sources of NPY that mediate adipose effects include the bloodstream, sympathetic nerve terminals that innervate the adipose tissue, as well as adipose tissue-derived cells. Understanding the role of central vs. peripherally-derived NPY in whole-body energy balance could shed light on mechanisms underlying the pathogenesis of obesity. This information may provide some insight into searching for alternative therapeutic strategies for the treatment of obesity and associated diseases.